Crystalline Polyester Toner Resin Low Temperature Fixing
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Solution Overview
Problem
Current toner technologies for electrophotography face challenges in achieving low temperature fixing while maintaining image retainability and preventing toner blocking, with existing crystalline polyester resins having limitations in charging properties under high temperature and high humidity conditions.
Innovation Solution
A toner comprising a binder resin with a crystalline polyester resin and a low-molecular compound having a naphthalene or biphenyl skeleton, where the crystalline polyester resin contains 0.5 to 30 construction mole % of an aromatic dicarboxylic acid-derived constitutional component, enhancing charging properties and resistance to deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the glass transition point of the binder resin is lowered to reduce fixing temperature, then low temperature fixability is improved, but toner blocking occurs during storage or in the developing machine
Solution Approach 1:
The invention changes the chemical composition parameters of the binder resin by incorporating specific polyester resins with controlled glass transition points (40-80°C) and melting points (60-120°C), along with polyolefin resins, to achieve a balanced formulation that enables low temperature fixing while preventing toner blocking during storage and development
Solution Approach 2:
The invention uses a composite binder resin system combining polyester resin and polyolefin resin in specific ratios (polyester resin 30-80 mass%, polyolefin resin 20-70 mass%), creating a material that exhibits both low temperature fixability and blocking resistance through the synergistic effects of the component resins
2Temperature
If a crystalline polyester resin with low melting point is used to achieve low temperature fixing, then fixing temperature is reduced, but charging properties deteriorate under high temperature and high humidity conditions
Solution Approach 1:
The invention optimizes the molecular weight and compositional parameters of the crystalline polyester resin, controlling the glass transition point (40-80°C) and melting point (60-120°C) to achieve a balance between low temperature fixing capability and stable charging properties under varying environmental conditions including high temperature and high humidity
Solution Approach 2:
The invention introduces functional additives with specific local properties (charge controlling agents, releasing agents, and inorganic particles) into the toner composition to compensate for charging property deterioration in specific environmental conditions, while maintaining the low melting point characteristic of the crystalline polyester resin for low temperature fixing
3Temperature
If the glass transition point is lowered below 50°C to reduce fixing temperature, then low temperature fixability is improved, but image retainability is impaired
Solution Approach 1:
The invention precisely controls the glass transition point within 40-80°C and melting point within 60-120°C for the crystalline polyester resin, optimizing these thermal parameters to achieve sufficient low temperature fixability while maintaining adequate image retainability through the controlled phase transition behavior of the binder resin
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides improved charging properties and resistance to deformation, enabling low temperature fixing while maintaining image quality and stability under varying environmental conditions.
Implementation Method 1
a technique of lowering the glass transition point of a resin for a toner (binder resin)... lowering the glass transition point... the glass transition point is a design feature of resins for toner... the melting point of the crystalline polyester resin is 60° C. or higher and 120° C. or lower
Data Source
AI summary
A toner for electrophotography contains a binder resin and a coloring agent, and is characterized in that the binder resin contains a crystalline polyester resin, and a low-molecular compound having at least one of a naphthalene skeleton and a biphenyl skeleton, and the crystalline polyester resin contains 0.5 to 30 construction mole % of an aromatic dicarboxylic acid-derived constitutional component. Further, a developer for electrophotography and an image forming method using the toner for electrophotography are disclosed.